Electric-motor brake.



A. E. HANDY.

ELECTRIC. MOTOR BRAKE. APPLICATION FILED JULY 23.1912.

I/Il III/IIIIIII,

Patented Apr. 6, 1915..

witnesses:

5] wue wto g v 3514A; atto'wlug UNITED STATES PATENT OFFICE.

ARTHUR n. HANDY, or BROOKLYN, NEW roux, ASSIGNOR TO 0111s ELEVATOR COMPANY, or .mnsnr orrY, NEW'J'ERSEY, A. coaronerxow or NEW'JERSEY.

uremic-Moron BRAKE.

To all whom it may concern Be it known that I, ARTHUR E. HANDY, a

citizen of the United States, residing at of a simple, self-contained, practical and 'efficient brake for electric motors.

A further object is the provision of a motor brake which is operated by the magnetic flux of the motor.

Other objects of my invention will appear from the following description which, taken in connection with the accompanying drawing, sets forth one form in which it may be embodied.

i The drawing shows, in a diagrammatic 'way, my invention as applied to a reversing alternating current electric motor, and it will be apparent that the invention is also applicable to any electric motor.

Referring to the drawing, Figure 1 is a sectional elevation-a1 side view of an alternating current motor containing an embodiment of my invention, Fig. 2 is an end view of Fig. 1; Fig. 3 is an end sectional view of Fig. 1, the sectionbeing taken on the broken line (II-a, looking in the direction of the arrows.

The motor comprises a casing 1 to-each side of which is bolted a cover 2 and 3 car rying bearings 4 and 5, respectively. These bearings support a shaft 11 to which is secured a spider 8 carrying the laminae? which form the rotor of the motor. While the rotor may be wound in any desired manner, I have, for the sake of simplicity, illustrated the same as the familiar squirrel cage type, comprising a series of copper rods 9 buried in corresponding holes in the rotor adjacent the periphery thereof, the rods being electrically short circuited by means of copper rings 10'as is the usual practice in this type ofniotor. The motor stator comprises a laminated ring 6 rigidly secured in the motor casing and provided with slots 12 (seeFig. 3), which are adapted to receive the usual stator windings. The laminated stator ring 6 is of greater axial lengththan'that of the rotor so as to embrace vor encircle a metal ring 13 secured upon a sleeve 14 which is adapted to rotate upon that part of the Specification of- Letters Patent.

tened the cam 23. supported by the cover 3 of the motor and Patented Apr. 6, 1915.

Application filed m 23, 1912. SerialjNo. 711,032.

bearing 5 which extends into the motor cas- 'ng. A washer'15 is located on the motor shaft between therotor. and the metal ring 13 andits function is to maintain the latter against 'bodily' -movement. The metal ring 13 may besol-id, or itmay be, and preferably is, of built-upor laminated construction as shown, similar to that of the rotor, and like that member, it is preferably provided with a suitable winding such as a squirrel cage winding comprising the bars 15 and the short-circuit rings 16. The ring 13 is operatively I connected to any suitable motor brake such as is shown herewith. This brake comprises a brake pulley 17 keyed or other-v wise secured to the shaft 11 and rotating therewith, and a pair of brake shoes 202U arranged on opposite sides of the periphery of the brake pulley and carried upon a air of' brake levers 18-18. The upper end of each brake lever is pivoted upon a stud 19 which'is carried by the motor cover 3, and the lower ends of the brake levers approach each other and extend downwardly so as to' form the parallel members .22-22, between which'is located a brake operating cam 23. Brake springs 2525 are carried upon a rod 21 which passes through both of the brake members 22, 22, and is provided with a collar or washer 26 and tension adjusting nuts 27 upon each end. The springs acting against the members 22, 22 tend tocarry the brake shoes into frictional engagement with the periphery of the brake pulley and prevent the latter from rotating, and in order to elfect'the release of the brake shoes I provide an operative connection between the metalring 13 and the cam 23. This connectioncomprises a shaft 24:,to one end of which is keyed or otherwise securely fas- The shaft is rotatably carries upon its other end an internal gear sector 28 which is adapted to mesh with a spur gear 29 formed integral with the'sleeve 1 1 as shown, or made separate if'desired, but connected thereto. In order to limit the movement of the sector 28 and consequently that of the ring'13 and brake cam 23, I provide a pair of oppositely disposed adjusting screws 30, 30, which maybe threaded into the motor casing 1 and engaged by bosses 31, 31, upon the sector as the latter is moved from a central position to either side when the motor reverses.

Since the metal ring 13 is embraced by the stator 6, it follows that this ring will be subjected to a turning moment similar to that of the rotor, due to the magnetic flux set up by the energization of the stator windings when the motor circuit is closed. The turning moment imparted to the ring 13, acting through the gear 29 and sect-or 28, tends to rotate the shaft 24 and cam'23, and the latter will tend to move apart the brake members 22, 22, and thereby release the brake shoes from frictional engagement with the brake pulley, and the motor shaft will be free to rotate. It will be observed that the adjustingscrews, 30, 30, limit the movement of ,the sector 28, and hence the ring 13 v and cam 23 will likewise have a limited through the came 23, shaft 24, sector 28, and

spur gear29 and the brake will again be applied. If the motor is reversed the ring 13 will also tend to reverse its direction of rotative movement and the cam 23 likewise.

, Thus it is seen that the brake will be released'every time the motor is started irrespective of 1ts direction of rotation.

Heretofore it has been the usual practice 7 to employ a separate magnetic device for releasing a motor brake which device requires considerable current for its operation, particularly where an alternating current is employed. The same is expensive to use and construct, adds an unnecessary complication and often fails to operate properly, due to p the effects of. residual magnetism and othercauses. Then'ag'ain its action is not dependent upon the motor, for its'operation, but upon some electro-responsive device such as a circuit closing switch, which, while arranged simultaneously to operate concurrently with that of the motor, may or may not do so. Myinvention provides a motor brake apparatus which is operated by and concurrently with the motor'under all conditions. That is to say, the brake is released by the same means which causes the motor to operate, and is applied to stop or retard the motor every time the circuit of the latter is interrupted or its magnetic strength becomes excessively weakened. For this reason my invention is particularly adapted to electric elevators although it may have a general application. v I

The ring 13, as before pointed out, may

be made in a variety of ways provided it will tend torotate when the motor is energized. 'Its torque may @be very moderate ture and field magnet, a brake for the motor ple and effective mechanical connection be-' tween the ring 13 and brake cam 23, ,comprising the gear 29 and the internal gear sector 28, it is obvious that various other mechanical devices could just as well be used to eii'ect the desired results. In fact various changes and modifications could be made in the apparatus by'one skilled in the art with: out departing from the spirit and scope of my invention.

What I claim and desire to secure by Let ters Patent of the United States is 1. An electric motor comprising an armaarmature, a rotary member concentric with the armature in the path of the magnetic flux of the said field magnet, and an operative connection between said member and the brake. v

2. An electric motor comprising an armature and field magnet, a brake for the motor armature, a rotary member concentric with the. armature in the path of the magnetic flux of the said field magnet, an operative and means for limiting the movement of said member.

3'. An electric motor comprising an armature and field magnet, a brake for the motor armature, a rotary member in the path of the magnetic flux of the said field magnet, an operative connection between said member and brake, and adjustable means for permitting a predetermined movement of said member.

4. An electric motor comprising a stator and a plurality of rotors, a brake for one of the rotors, and means controlled by another of the rotors for operating said brake.

5. An electric motor comprising a field magnet and armature, an armature shaft, a brake for the armature, a member adapted to rotate with respect to said shaft, and an operative and brake.

6. An electric motor comprising a field magnet and armature, an armature shaft, a shaft bearing, a brakefor the armature, a

connection between said member and brake,

connection between said member member rotatively mounted on said bearing and connected to operate the brake, and means operative'upon the excitation of said field magnet for rotating said member.

7 An electric motor comprising an armature and field magnet, a brake for the motor means for imparting a torque in said addi-' 8. An alternating current electric motor comprising 'a stator-and rotor, a rotor shaft, a brake for the shaft, a rotary member embraced by the stator and connected to operate said brake, and inductive means comprising conductors on the said rotary member-for imparting a torque to said rotary member to efiect the operation of the brakes 9. An alternating current motor comprising a stator, a motor shaft, 3 991 91 secured to the shaft, an, additioifil' rotor embraced by the -stator and having a movement relative to the said shaft, a brake for the motor shaft, operatively connected to said additional rotor, and means for inducing a torque in saidadditional rotor upon the excitation of said motor stator to effect the operation of the brake, said means compris ing conductors on the additional rotor.

10. A11 alternating current motor comprising a stator, a motor shaft, a rotor se- T ,cured to the shaft, an additional rotor em braced by the stator and having a movement relative to the said shaft, a brake for the motor shaft, a reduction-gear connection'between .said additional rotor and brake, and

tional rotor to effect the operation of the said rotors.

brak said means comprising conductors on the a ditional rotor.

11. In an electric motor, the combination of a-shaft, a rotor secured to said'shaft, an additional rotorarranged to 'rotatewith respect to said shaft, a field magnet for said motor embracing both of said rotors, a brake for the motor, and an operative connection between said brake and one of ARTHUR E. HANDY,

Witnesses a J. F. RULE,

W. A. DALY.

shaft, a stator embracing both 

